<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>单标签！纯CSS实现动态晴阴雨雪</title>
</head>

<body>
    <div class="weather sunny"></div>
    <div class="weather cloudy"></div>
    <div class="weather rainy"></div>
    <div class="weather snowy"></div>
</body>
<style>
.weather {
    position: relative;
    display: inline-block;
    width: 180px;
    height: 240px;
    background: #23b7e5;
    border-radius: 8px;
}
.sunny:before {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: #F6D963;
    border-radius: 50%;
    box-shadow: 0 0 20px #ff0;
    z-index: 2;
}
.sunny:after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -45px 0 0 -45px; 
    width: 90px;
    height: 90px;
    background: #FFEB3B;
    clip-path: polygon(
    	50% 0%,
        65.43% 25%,
        93.3% 25%,
        78.87% 50%,
        93.3% 75%,
        64.43% 75%,
        50% 100%,
        35.57% 75%,
        6.7% 75%,
        21.13% 50%,
        6.7% 25%,
        35.57% 25%);
    z-index: 1;
    animation: sunScale 2s linear infinite;
}
@keyframes sunScale {
    0% {
        transform: scale(1);
    }
    50% {
    	transform: scale(1.1);
    }
    100% {
        transform: scale(1);
    }
}
.cloudy:before,
.rainy:before,
.snowy:before {
    content: "";
    position: absolute;
    top: 50%;
    left: 25%;
    transform: translate(-50%, -50%);
    width: 36px;
    height: 36px;
    background: #fff;
    border-radius: 50%;
    box-shadow: 
    	#fff 22px -15px 0 6px,
    	#fff 57px -6px 0 2px, 
    	#fff 87px 4px 0 -4px,
    	#fff 33px 6px 0 6px,
    	#fff 61px 6px 0 2px,
    	#ccc 29px -23px 0 6px,
    	#ccc 64px -14px 0 2px,
    	#ccc 94px -4px 0 -4px;
    z-index: 2;
}
.cloudy:before {
    animation: cloudMove 2s linear infinite;
}
@keyframes cloudMove {
    0% {
        transform: translate(-50%, -50%);
    }
    50% {
        transform: translate(-50%, -60%);
    }
    100% {
        transform: translate(-50%, -50%);
    }
}
.rainy:after {
	content: "";
    position: absolute;
    top:50%;
    left: 25%;
    width: 4px;
    height: 14px;
    background: #fff;
    border-radius: 2px;
    box-shadow:
    	#fff 25px -10px 0,
    	#fff 50px 0 0,
    	#fff 75px -10px 0,
    	#fff 0 25px 0,
    	#fff 25px 15px 0,
    	#fff 50px 25px 0,
    	#fff 75px 15px 0,
    	#fff 0 50px 0,
    	#fff 25px 40px 0,
    	#fff 50px 50px 0,
    	#fff 75px 40px 0;
    animation: rainDrop 2s linear infinite;	
}
@keyframes rainDrop {
    0% {
        transform: translate(0, 0) rotate(10deg);
    }
    100% {
        transform: translate(-4px, 24px) rotate(10deg);
        box-shadow:
        #fff 25px -10px 0,
        #fff 50px 0 0,
        #fff 75px -10px 0,
        #fff 0 25px 0,
        #fff 25px 15px 0,
        #fff 50px 25px 0,
        #fff 75px 15px 0,
        rgba(255, 255, 255, 0) 0 50px 0,
        rgba(255, 255, 255, 0) 25px 40px 0,
        rgba(255, 255, 255, 0) 50px 50px 0,
        rgba(255, 255, 255, 0) 75px 40px 0;
    }
}
.snowy:after {
    content: "";
    position: absolute;
    top:50%;
    left: 25%;
    width: 8px;
    height: 8px;
    background: #fff;
    border-radius: 50%;
    box-shadow:
        #fff 25px -10px 0,
        #fff 50px 0 0,
        #fff 75px -10px 0,
        #fff 0 25px 0,
        #fff 25px 15px 0,
        #fff 50px 25px 0,
        #fff 75px 15px 0,
        #fff 0 50px 0,
        #fff 25px 40px 0,
        #fff 50px 50px 0,
        #fff 75px 40px 0;
    animation: snowDrop 2s linear infinite; 
}
@keyframes snowDrop {
    0% {
        transform: translateY(0);
    }
    100% {
        transform: translateY(25px);
        box-shadow:
        #fff 25px -10px 0,
        #fff 50px 0 0,
        #fff 75px -10px 0,
        #fff 0 25px 0,
        #fff 25px 15px 0,
        #fff 50px 25px 0,
        #fff 75px 15px 0,
        rgba(255, 255, 255, 0) 0 50px 0,
        rgba(255, 255, 255, 0) 25px 40px 0,
        rgba(255, 255, 255, 0) 50px 50px 0,
        rgba(255, 255, 255, 0) 75px 40px 0;
    }
}
</style>
</html>
